/*
 * Copyright 2011-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.sabayframework.queue.impl;

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

/**
 * Synchronization helper class.
 * 
 * @author Alex Antonau
 * */
public final class Monitor {

	private final Lock lock;
    private final Condition changed;
	
	public Monitor() {
		lock = new ReentrantLock();
        changed =  lock.newCondition();
	}
	
	public void lock() {
		lock.lock();
	}
	public void lockInterruptibly() throws InterruptedException {
		lock.lockInterruptibly();
	}

	public boolean tryLock() {
		return lock.tryLock();
	}

	public void unlock() {
		lock.unlock();
	}

	public void changed(){
		lock.lock();
		try{
			changed.signal();
		}finally{
			lock.unlock();
		}
	}
	public void waitChanged(long timeout) throws InterruptedException{
		lock.lock();
		try{
			changed.await(timeout, TimeUnit.MILLISECONDS);
		}finally{
			lock.unlock();
		}
	}
	public void waitChanged() throws InterruptedException{
		lock.lock();
		try{
			changed.await();
		}finally{
			lock.unlock();
		}
	}
	
}
